The present invention relates to stripping baths for removal of protective films from substrates. More particularly, the present invention relates to a non-intrusive method of film removal of an organic coating from a substrate.
Organic coatings are used to retard the corrosive effects of air and water on substrates such as metal or the like. Specifically, organic coatings such as electrophoretically applied coatings are used to cover and protect bright plating for various parts. When applied properly, an organic coating can greatly extend the working life of a metal or metal plating, thereby enhancing the usefulness and durability of the actual part.
Occasionally during coating and processing of such coated parts, it is necessary to remove the coatings, either because the coatings themselves are improperly formed on the parts or the parts themselves require further processing or the like.
Typically, two methods of removing these coatings are used: caustic baths and halogenated solvents.
In the use of highly caustic stripping baths, it is necessary to utilize elevated temperatures and very limited periods of time in order to effectively process parts for stripping of these coatings. However, due to the highly caustic nature of the chemicals and the activity temperatures used, if the process controls are not watched very carefully, the caustic may often times begin to corrode or otherwise harm the underlying metal surface. Such a problem may then require further buffing, plating or other processing, which in turn is very costly.
Thus, these caustic type baths are potentially damaging to substrates and provide many obstacles to effective use in a production situation.
A second process which may be used in the removal of organic coatings from substrates is the use of halogenated solvents. While halogenated solvents work well at low temperatures, they are subject to much volatilization and require strict environmental control, including volatile reclaiming units or the like. Also, because these halogenated solvents have been subject to environmental concerns in recent years, they are being phased out from industrial processes. Thus, replacement of such systems is inevitable.
It is a goal in the art to provide a more effective and less corrosive environment for removal of organic coatings from substrates.